I think everyone here has given you good advice, even Leon Willet who is a top-notch orchestrator. It takes dedication and work, but if you love music, you'll be rewarded handsomely for your efforts. Working with a teacher is always best, but if that's not an option, you could learn on your own if you're diligent enough. A piano book to start with:I have zero musical education - whatsoever.
I may have a good ear, but I do not know what or why I'm doing the harmonization the way I do. I just listen if it feels "right".
You can find the following series here (under pdf)
You can find other scores on IMSLP such as Bela Bartok's book for Children.
On the internet, the course HeliaVox suggests above is top notch and free. And Theory.net for additional knowledge and reading practice (check settings on the upper right).
Vaughan Williams has some simple piano and choral pieces too but this is not the place to start.